Bone fixation methods and devices

ABSTRACT

Bone fixation systems and methods are provided herein. A system may include a plate, having at least one face configured to be affixed to a bone surface, and an adhesive for affixing the plate to a bone surface. In some examples, the plate may include at least on indentation on its face, such as a dimple. The system may also include an application device for dispensing adhesive onto a plate or bone surface, which may include a chamber for containing the adhesive, a heating element in communication with the chamber, a nozzle for dispensing the adhesive, a piston slidably disposed within the chamber for advancing the adhesive towards the nozzle, and a control mechanism for controlling release of adhesive from the nozzle.

PRIORITY OF THE INVENTION

This application is a continuation of U.S. Patent Application Ser. No.14/465,566, filed on Aug. 21, 2014, and entitled Bone Fixation Methodsand Devices.

BACKGROUND

Unless otherwise indicated herein, the materials described in thissection are not prior art to the claims in this application and are notadmitted to be prior art by inclusion in this section.

Craniomaxillofacial surgery is performed routinely in the United Statesand around the world for numerous problems involving the skull,including craniosynostosis (premature fusion of the cranial sutures),skull deformities associated with syndromes such as Crouzon Syndrome andApert Syndrome; skull deformities resulting from the resection of bothbenign and malignant tumors, and complex craniofacial trauma involvingthe bones of the face and skull. These surgeries may involve thealteration or correction of the shape and structure of the skull, faceand jaws and often require the repair, manipulation and fixation ofbone.

Presently, the approximation and fixation of bone is typicallyaccomplished with mechanical fastening systems, such as screws andplates. Tissue conditions, limited space, and access to the surgicalsite often present particular challenges to the practitioner. Forexample, in some cases, mechanical fixation is complicated or evenprevented altogether due to a lack of tissue surface area or tissuesubstrate depth sufficient to anchor an adequate secure location for thefixation device. In addition, standard mechanical attachment methods inthe context of bone repairs involve a series of labor intensive andsometimes complicated tasks.

At present, several types of craniofacial surgery plating systems arecurrently commercially available. Both titanium and resorbablepolymer-based systems utilizing plates and screws are routinely utilizedfor the stabilization of bones during reconstruction in variouscraniomaxillofacial surgeries. These systems, however, often requirecumbersome power equipment that necessitates additional operating roomstaff training and additional surgical time that increases the cost ofthe operating room, anesthesia time and surgical time. Sonic weldingproducts, such as the Sonic Weld™ produced by KLS Martin, utilize aplate and resorbable tacks inserted into a hole drilled into the bonetissue and welded in place with an ultrasonic welding device. Whilethese products do not use screws, holes must still be drilled into thebone tissue for placement of the tacks, which melt and disseminate intothe trabecula of the bone with unknown consequences on growth anddevelopment.

The type, weight and amount of material used in plating presentadditional challenges. Internal fixation devices, such as those used incraniomaxillofacial surgery historically have been made of variousmaterials including metals such as titanium. Polylactic acid orpolylactide polymers, such as poly(L-lactic acid) (PLLA) andpoly(lactic-co-glycolide) (PLGA) have also been used in implantabledevices. As compared to metallic devices, fixation devices made of thesetypes of polymers do not corrode, can be constructed to avoid stressyielding, and are resorbable. Further, these devices may be particularlyuseful in the pediatric patient population as their resorptioneliminates any adverse or restrictive effect that permanent plates wouldimpose on craniomaxillofacial growth and development. Resorption ofplates and screws fabricated from these polymers occurs approximately 2years following placement. While use of biodegradable and absorbablematerials is preferred by the surgical community, many of the existingmechanical systems are fabricated from metal and are non-resorbable.Conventional plating systems utilizing screws can often weaken theunderlying bone or tissue, leading to decreased trabecular bone score.In some cases, failure of the screws can occur. Further, the thicknessof these devices necessary to support screws, and the screws themselves,may be uncomfortable for the patient, be visible from the outer tissuesurface, or interfere with healing,

Although some tools and materials have been developed to overcome thechallenges and shortcomings described above, the fixation devices arestill often bulky and cumbersome and time consuming to implant. A needstill exists for a method and device that can eliminate the need forscrews, but still provide satisfactory bony stabilization forcraniofacial reconstruction and other reconstructive or orthopedicsurgeries by (1) simplifying and expediting the intra-operativeapplication of plates to the bone, and (2) removing the need fordrilling holes in the bone tissue, thereby obviating the need for bulkypower drilling equipment. Such a method and device would eliminate manyof the surgical steps required to place mechanical fixation devices. Inparticular, drilling, tapping to produce threading, and placement offixation pins or screws would no longer be necessary. Further, a devicewhich utilizes a biocompatible, absorbable and lightweight polymermaterial may also address many of the above issues. It may also beuseful to provide an internal fixation system that contributes to thequality of bone healing by the administration of growth factors or otherbiologically-active (bioactive) molecules.

SUMMARY OF THE INVENTION

Novel systems and methods for repairing bone defects using an applicatordevice for dispensing a melted adhesive either directly on the bonetissue as the fixation means, or in combination with a bone plate, aredescribed herein. The adhesive can be any heat-meltable, bioabsorbablematerial. In some cases, the adhesive is provided as or includes apolymer material, such as polylactic acid) (“PLA”) or a PLA-basedpolymer such as poly-DL-lactide (PDLLA). Many sizes and shapes of platesmay also be provided and selected by a surgeon based on his or herpreference or to meet a particular surgical need. For example, platesmay be arc or cross-shaped, or may be cut-to-size from a sheet or spoolof plate material. The applicator device is configured to melt anddispense the adhesive in a controlled manner, in some embodiments, theapplicator device may include a control mechanism for dispensing preciseamounts of adhesive and ensuring that excess adhesive is not dispensedonto the bone or plate. The device may be provided in the form asurgical tool that can be operated with one hand, leaving a free handfor the surgeon to manipulate the tissue or plate.

Some embodiments of the present disclosure provide a system including:(i) plate having at least one face configured to be affixed to a bonesurface; and (ii) an adhesive for affixing the plate to a bone surface.

Further embodiments of the present disclosure provide a methodincluding: (i) applying an adhesive in a melted state to a first bonesegment and a second bone segment in abutment with the first bonesegment; and (ii) setting or curing the adhesive thereby affixing thefirst bone segment to the second bone segment.

Further embodiments of the present disclosure provide a methodincluding: (i) applying a bioabsorbable polymer adhesive in a meltedstate to a plate configured to be affixed to a bone; (ii) bringing theplate into contact with a first bone segment and a second bone segmentin abutment with the first bone; and (iii) curing the adhesive therebyaffixing the plate to the first bone segment and to the second bonesegment.

Still further embodiments of the present disclosure provide a fixationdevice, including a plate having at least one face configured to beaffixed to a bone surface, the at least one face having a plurality ofindentations or “dimples” for receiving an amount of adhesive.

These as well as other aspects, advantages, and alternatives, willbecome apparent to those of ordinary skill in the art by reading thefollowing detailed description, with reference where appropriate to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of an example system.

FIG. 2 illustrates an example plate for use in the system of FIG. 1.

FIG. 3 illustrates an example plate for use in the system of FIG. 1.

FIG. 4 illustrates an example plate for use in the system of FIG. 1.

FIG. 5 illustrates an example plate for use in the system of FIG. 1.

FIG. 6 illustrates an example plate for use in the system of FIG. 1.

FIG. 7 illustrates an example plate for use in the system of FIG. 1.

FIG. 8 illustrates an example plate for use in the system of FIG. 1.

FIG. 9 illustrates an example plate for use in the system of FIG. 1,

FIG. 10 illustrates an example plate for use in the system of FIG. 1.

FIG. 11 illustrates an example plate for use in the system of FIG. 1,

FIG. 12 is a cross-sectional view of an example application device foruse in the system of FIG. 1.

FIG. 13A is a side view of a component of an example application devicefor use in the system of FIG. 1.

FIG. 13B is a front view of a component of an example application devicefor use in the system of FIG. 1.

FIG. 13C is a side cross-sectional view taken along line A-A of acomponent of an example application device for use in the system of FIG.1.

FIG. 13D is a perspective view of a component of an example applicationdevice for use in the system of FIG. 1.

FIG. 14 is a side partial cross-sectional view of a portion of anexample application device for use in the system of FIG. 1, shownapplying a bead of adhesive to a fixation device.

FIG. 15 is a view of an example plate for use in the system of FIG. 1,shown with beads of adhesive being applied thereto.

FIG. 16A is a side partial cross-sectional view of a portion of anexample application device for use in the system of FIG. 1, shownapplying a ribbon of adhesive to a fixation device.

FIG. 16B is a front view of a ribbon of adhesive applied to a fixationdevice,

FIG. 17 illustrates an example method for joining bone segments.

FIG. 18 is a flowchart of an example method.

FIG. 19 illustrates an example method for joining bone segments.

FIG. 20 is a flowchart of an example method.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying figures, which form a part hereof. In the figures, similarsymbols typically identify similar components, unless context dictatesotherwise. The illustrative embodiments described in the detaileddescription, figures, and claims are not meant to be limiting. Otherembodiments may be utilized, and other changes may be made, withoutdeparting from the scope of the subject matter presented herein. It willbe readily understood that the aspects of the present disclosure, asgenerally described herein, and illustrated in the figures, can bearranged, substituted, combined, separated, and designed in a widevariety of different configurations, all of which are explicitlycontemplated herein.

I. Overview

Novel systems, devices and methods for repairing bone defects aredescribed herein. Example methods may include dispensing an adhesivedirectly on a bone surface as the fixation means, or using the adhesiveto affix a fixation device, such as a bone plate, to the surface of oneor more bone segments. The plate is affixed, in one example, by applyingthe adhesive in a melted state and holding the plate in place while itcures or hardens. Where the adhesive alone is used to affix bonesegments together or fill in a void, the adhesive material is applied toeach of the bone segments. Both example methods can be utilized in anumber of geometrically varied bone shapes.

The described systems and methods may overcome many of the shortcomingsdescribed above by eliminating the need for screws, pins or otherimplements which must be physically driven into the bone tissue and alsoby eliminating the need for the secondary operation of drilling holes toreceive these fastening implements in the bone. This may not only reducethe potential for damage to bony segments, but may also maintain theresorption characteristics of the bone plate. Moreover, the need forbulky and expensive bone drills for affixing the bone plates and thetime associated with drilling holes in the bone is also eliminated.

Eliminating the use of screws and pins also provides considerableflexibility in the size and shape of the bone plates. The thickness ofthe plates may also be reduced while still maintaining superior tensileand mechanical properties such as stiffness, toughness and elongation tobreak. In some cases, the bone plates may include one or moreindentations, such as dimples or grooves, for receiving the adhesive,which may include any biocompatible and absorbable adhesive. Theseindentations provide a convenient guide for dispensing precise amountsof the adhesive to the plates and, in some cases, in defined patterns.Further, the bone plates may provide a vessel for controlled delivery ofone or more medicinal agents to the surgical site. In some embodiments,the plate may include a bioactive portion, which may be porous, that isimpregnated with one or more medicinal agents. The term “medicinalagent” as used herein should be understood broadly to include anysubstances having any biologic, pharmacological, remedial, prophylactic,analgesic, therapeutic, preventative, or curative properties.

Adhesive may be applied to the bone surface or bone plates using a novelapplication device. The system may also include a novel applicationdevice for heating and dispensing the adhesive onto a fixation device oronto the bone surface. In one example, the application device is in theform of a hand held surgical tool that can process the heating of theadhesive material and then deliver the material to the surgical site.The device used for delivery of the materials includes a novel controlmechanism and features to implement an effective bone repair. The devicemay be manipulated and adhesive dispensed with a single hand so that theoperator may have a free hand to position the bone plate or bonesegments. Further, operation of the device may be simple such that itmay be readily used, not only by surgeons, but also trained technicians.To this end, the application device may also include a control mechanismfor dispensing precise amounts of the adhesive to the desired location.One challenge presented with low viscosity and flowing materials, suchas a melted adhesive, is that the material tends to continue flowing andresist clean termination, even when the material is no longer beingactively dispensed from its container. This may be observed as “threads”or “strings” of adhesive that may stretch between a dispensed amount ofthe adhesive and its container. Because this may be undesirable in asurgical setting, the control mechanism may allow for precisemanipulation of the adhesive.

It should be understood that the above embodiments, and otherembodiments described herein, are provided for explanatory purposes, andare not intended to be limiting.

II. Example Systems

An example system 100, shown in FIG. 1, may include a fixation device110 and an adhesive 120. The fixation device 110 may be any implantabledevice suitable for being affixed to a bone surface for the repair orjoining of one or more bone segments. Using the adhesive 120, thefixation device 110 may be affixed to a bone surface without the use ofscrews or other fixation implements requiring drilling or physicallypenetrating into the bone. In some embodiments, the fixation device 110may be a plate 130 having at least one face 132 for being affixed to abone surface. As will be described in more detail below, plate 130 maybe provided in a number of shapes, sizes and materials and may includeone or more surface structures or treatments. The plates 130 can be usedin a variety of applications, such as in craniomaxillofacial proceduresfor the fixation and stabilization of segments of bone of thecraniomaxillofacial skeleton during reconstructive surgery. In anotherembodiment, the bone plates 130 may be used in treating hand fracturesor in conjunction with osteotomies.

Various biocompatible adhesives 120 can be used to affix the fixationdevice 110 to a bone surface. The adhesive 120 may be selected toprovide a sufficient mechanical bond either between two bone segments,or between a fixation device 110 and a bone surface. Where the adhesive120 is used to affix a fixation device 110 to a bone surface, theadhesive must provide sufficient resistance to the fixation device 110pulling away from the bone surface. Further, as the system 100 is usedin a surgical setting to repair bone defects, the adhesive 120 may beselected to cure in a moist environment. In some cases, however, thebond provided by the adhesive 120 may need to be broken. The mechanicalbond properties of the adhesive 12.0 must be balanced against thepotential need for repositioning a bone plate 130 once it has beenaffixed to a bone surface. As such, an adhesive 120 may be formulated tobe removable, such as with a Freer or Obwegeser elevator, if theposition of the plate 130 is not desirable.

The adhesive 120 is bioabsorbable so that the fixation device 110 andadhesive 120 need not be removed from the body. The adhesive 120 shouldmaintain its mechanical bond and not absorb before the bone segmentshave had sufficient time to join. For example, the adhesive may absorbwithin 6 to 8 weeks. Alternatively, the adhesive may take up to 1.5 to2.5 years to absorb. The selected adhesive may be customized to fit therequirements and characteristics of the particular application. In somecases, the absorbability of the adhesive may be selected to match thebioabsorability of the plate, as will be described further below.

Heat-meltable adhesives 120 may also be used. As shown in FIG. 1, theadhesive 120 may initially be in a solid state and may, in someembodiments, be melted in and dispensed from an application device 140onto the fixation device 110 or bone surface. In surgical settings,temperatures up to 2000° C. are regularly used in hemostasis orelectrocaudory procedures. Accordingly, the heat-meltable adhesive mayhave a melting point up to 2000° C. In other examples, the adhesive mayhave a melting point between 60 and 90° C. The adhesive 120 may also beselected to have a melting point at or below 60° C.

Specific examples of adhesives 120 for use in the system 100 may includeheat-meltable polymers, such as poly-DL-lactide (PDLLA), Poly(lacticacid (PLA) and polyester-based polymers. Polymer blends, such as PLA anda polyester (e.g., poly(ethylene/butylene succinate) may also be used.In particular, the adhesive 120 may comprise a polymer blend, such asthe polymer blend(s) described in patent application U.S. patentapplication Ser. No. 11/787,076 entitled: Novel Biodegradable BonePlates And Bonding Systems, which is hereby incorporated by reference inits entirety. The adhesive 120 may comprise a combination of one or moreof the above.

The system 100 may also include an application device 140 for dispensingthe adhesive 120 onto one or more of a bone surface and the fixationdevice 110. Adhesive 120, in either a solid or flowable form, may beintroduced into the application device 140 via an opening 142 to aninternal chamber (not shown), which may be sealed with a closure 144. Auser may hold the application device 140 by a grip portion 148 andadvance adhesive within the chamber towards a nozzle 146 via trigger150. In some examples, solid adhesive 120 may be melted inside of thechamber and dispensed from the application device 140. Accordingly, theapplication device may include an electrical connection 152. Furtherdetails of the application device will be discussed below.

III. Example Plates

Various example plates 130-1130 are shown in FIGS. 1-11. The plates 130may be fabricated in a number of sizes and shapes from which a surgeonmay select according to the type and parameters of the repair and needsof the patient. FIG. 1 shows a bone plate having a generally arcuateshape. FIG. 2 shows a bone plate 230 in the shape of an elongate rod.FIG. 3 shows another example bone plate 330 having an elongated body 332with one or more members 334 extending from the ends of the body. Themembers 334 may terminate in pads 336 for receiving adhesive 120. FIG. 4shows a bone plate 430 that is generally rectangular in shape. The endsof the plate 430 may be fabricated or cut at various angles, dependingon the requirements of the surgical procedure. FIG. 5 shows a plate 530in the shape of an elongate disk. FIG. 6 shows a hone plate 630 that isgenerally square in shape. FIG. 7 depicts a bone plate 730 that iscross-shaped. Various polygonal shapes may also be used, for example,the hexagon-shaped bone plate 830 shown in FIG. 8. Many other shapes,such as “T ” “Y” and “L” shaped plates are also contemplated. The platescan also be fabricated in a number of thicknesses. In some examples, theplate may be between 1 mm and 1.5 mm thick,

It is also contemplated that bone plates may be cut to size and shapefrom a substrate material to suit the needs of the particular patient,area of placement, and procedure. In some examples, the substrate may befabricated in larger sheets or as a tape that can be cut to size andtailored to the preferences of the surgeon, the type of surgery beingperformed, the characteristics of the bone or bones being repaired, andthe patient, etc. For example, the length, width and overall shape ofthe plate may be selected or adjusted to match or be appropriate for thelength and size of a particular bone defect or to bridge a gap betweenbone segments.

The plate material may be chosen to have different strengths,flexibilities, biodegradation and chemical release properties, all ofwhich may be chosen or customized based on a particular need andapplication. The material and mechanical properties of the platematerial may be chosen based on the size, shape, location and type ofbone defect and the age, weight and level of activity of the patient.For example, a patient with a low level of mobility (such as an infantor older adult) or a bone defect in a low-stress or movement area of thebody may not require a fastener with very high tensile strength.Similarly, a large or deep bone defect may demand a plate of larger sizeor higher strength than a small or superficial defect. Areas of the bodyin which the bones are under high strain may require a plate material ofa larger size or higher strength than bones that are under lower strain.

For some repairs and locations, it may be desirable to bend the plate tofit the curvature of the bone surface. As will be readily appreciated bythose of skill in the art, the integrity of a bone repair using theplate and adhesive system described herein may be maximized by tailoringshape of the plate to follow the shape of the bone being repaired. Forexample, the plate may be bent to match the curvature of a patient'sskull bones. Accordingly, a flexible material may also be selected forthe plate. Further, the requisite flexibility or malleability of somematerials may also be achieved by heating the plate, for example,between 40 to 60° C.

The plate may be fabricated from various biocompatible materials. Insome examples, bioabsorbable plastics such as poly-DL-lactide (PDLLA),polylactate, polyglycolide, polydioxane, polycaprolactone, or otherrelated classes of polymers may be used. Absorbable biocompatiblematerials may have the benefit of not requiring removal from the body,which often requires an additional surgical procedure. In someapplications, a plate which is more or less quickly biodegraded may beselected. The plates may be fabricated from a blend of bioabsorbablepolymer materials, such as blends of polylactic acid (PLA)-basedpolymers or copolymers and polymers or co-polymers of polyesters. Thetypes and amounts of polymers used in the blend can be selected lotailor the bioabsorbability and other properties of the plate.

As shown in FIGS. 9 and 10, the plates 930, 940 may also be providedwith one or more indentations 934, 1034. For example, the plate 930 mayhave a face 932, configured to be affixed to a bone surface, having aplurality of dimples 934 disposed thereon. FIG. 10 illustrates pluralityof grooves 1034 disposed on a face 1032 of the plate 1030. The dimples934 and grooves 1034 are designed to receive an amount of the adhesivetherein. Both the dimples 934 and grooves 1034 provide a convenientguide for loading the plates with the adhesive, not only with respect towhere the adhesive should optimally be placed, but also with respect tothe amount of adhesive that should be applied. Moreover, theindentations 934, 1034 may provide for a more robust mechanical bondbetween a plate and a bone surface. When dispensed, adhesive willaggregate into the indentations and a meniscus of adhesive will extendbeyond the surface of the plate.

The depth of the indentations maybe up to approximately 50% of the depthof the plate. For example, where the plate is 1.5 mm thick, theindentations may be between 0.5 and 0.75 mm deep. The indentations mayalso be provided in various numbers, arrangements, densities, aspectratios and patterns on the face of the plate. For example, as shown inFIG. 9, the dimples 934 may be arranged in one or more rows and columns.The dimples 934 in these one or more rows and columns may be aligned, asshown in FIG. 9. Alternatively, the dimples 934 may be provided in astaggered pattern on a face 932 of the plate 930. In some eases,staggering the dimples 934 may lend mechanical stability to the bondbetween the plate and the bone surface. The dimples 934 may be formed inmany sizes and may be arranged at various spacing. In one example, thedimples 934 may be approximately 3 mm in diameter and may be spacedapproximately 3 mm apart. Further, as shown in FIG. 10, the grooves 1034may be oriented along the length of the plate 1030. Alternatively, thegrooves 1034 may be oriented along the width of the plate 1030. Othertypes, numbers and arrangements of indentations are also contemplated.

In some examples, the plate may also be porous, for example, a mesh. Thesize of the pores (e.g., openings in the mesh) may be such that woundhealing and bone repair is minimally impacted and, in some cases,facilitated. Oxygenation may be used to create pores in the platematerial. Pore sizes may be chosen to allow adjacent tissue ingrowth topenetrate through the substrate on one side of the wound, attach tocells on the other side of the wound, and repair the site. In someexamples, pores may range in size from 50 μm to 1 mm. Use of a porousmaterial may permit more rapid resorption of the plates. Traditionalbioabsorbable materials take between 1.5 to 2.5 years to degrade.However, as bone healing occurs fully between 6 and 8 weeks following abone fixation procedure, fixation systems are not required beyond thistime point. Plate porosity may permit controlled plate resorption within3-6 months following placement, considerably earlier than otherresorbable plating systems. The bioabsorption properties of the platecan also be controlled based on the thickness of the plate. Generally,the thinner the plate, the more rapidly it will resorb.

Further, the plate may also include, be coated with, impregnated with orbe infused with medicinal agents, such as drugs or other substances thatmay be released as the plate material biodegrades. For example, themedicinal agents may include substances for promoting wound healing,such as growth factors, substances for decreasing blood viscosity,substances for reducing platelet aggregation, anti-inflammatories,analgesics, substances for promoting blood clotting or antiseptic,antimicrobial or antibacterial substances. More specifically, themedicinal went(s) may include vitamin A, a steroid and an antibiotic. Inembodiments where the plate is porous or includes a porous portion, thepores be impregnated with biologically-active (bioactive) molecules. Thesize of the pores, and hence the degree of porosity, can be selectivelycontrolled to permit medicinal agents of varying sizes to be impregnatedinto the structure of the plates. The medicinal agent(s) may also beencapsulated in nanospheres that are then loaded into or onto the platesfor time-release delivery of the agent(s).

As shown in FIG. 11 a plate 1130 may also be provided with a bioactiveportion 1132 and one or more adhesive portions 1134. In operation, thebioactive portion 1132, which may be impregnated with a medicinal agent,may be placed over a boundary between two adjacent bone segmentsintended to be joined. The one or more adhesive portions 1134 may beloaded with adhesive, such as in one or more dimples 1136, and affixedto the two adjacent bone segments on either side of the boundary. Inthis configuration, the adhesive will not interfere with the action ofthe medicinal agent on the bioactive segment.

The implants of the invention can be manufactured as a unitary whole, asfor example, by injection molding or may alternatively be made ascomponents to be assembled using the bonding system or systems disclosedherein.

The plates can be fabricated using numerous manufacturing routes. Forplates having standard sizes and shapes, many conventional processingtechniques can be used, including, but not limited to injection molding,compression molding, blow molding, themoforming, die pressing, slipcasting, electrochemical machining, laser cutting, water-jet machining,electrophoretic deposition, powder injection molding, sand casting,shell mold casting, lost foam casting, plaster-mold casting,ceramic-mold casting, investment casting, vacuum casting, permanent-moldcasting, slush casting, pressure casting, die casting, centrifugalcasting, squeeze casting, rolling, forging, swaging, extrusion, shearingspinning, and powder metallurgy compaction.

IV. Example Application Devices

An example application device 1200 for dispensing adhesive onto afixation device, such as a plate, or a bone surface is shown in FIGS. 12and 13A-13D. Application device 1200 may include a housing 1210enclosing a body 1220 defining a chamber 1222 therein for containing anadhesive, terminating in a nozzle 1230 from which the adhesive isdispensed. Adhesive may be advanced within the chamber by a piston 1240slidably disposed within the chamber. A gasket 1242 may also be providedat an end of the piston 1240 for sealing the piston 1230 within thechamber 1222. The application device 1200 may also include a controlmechanism 1250 for controlling release of adhesive from the nozzle 1230.

In one example, shown in FIG. 12, the control mechanism 1250 may includean actuator 1252, which may be similar to a trigger, having activeposition and a released position (FIG. 12). The actuator 1252 is inoperative communication with the piston 1240 such that depressing theactuator 1252, or moving it from the released position to an activeposition, causes the piston 1240 to advance within the chamber 1222towards the nozzle 1230. Because of its levered-orientation, depressingthe actuator 1252 towards the housing will cause the piston to be driventowards the nozzle. In operation, a user may manipulate the applicationdevice 1200 with a single hand by holding at a grip portion 1212 andcompressing the actuator with his or her fingers to dispense theadhesive. The control mechanism 1250 may also include a spring 1254 forbiasing the actuator in a released position, shown in FIG. 12. Releasingthe actuator retracts the piston within the chamber away from thenozzle, thereby creating a negative pressure within the chamber. Thisnegative pressure acts on the adhesive within the chamber, causing it tobe pulled back away from the nozzle. As such, the control mechanism 1250allows a user to dispense controlled amounts of adhesive from theapplication device 1200 and prevents additional adhesive from trailingout of the nozzle after the intended amount has been dispensed. Otherembodiments of the control mechanism 1250 are also contemplated. Forexample, the control mechanism 1250 may also include a blade-likeelement for physically cutting the string of adhesive or a shutter-likeelement for closing off the nozzle at a desired point.

An adhesive, such as any of those described above, in either a solid orflowable form, may be introduced into the chamber 1222. A solid adhesivemay be in the form of pellets, sticks or portions thereof. In someexamples, a solid adhesive may be melted or otherwise converted to aflowable form inside of the chamber, as shown in FIG. 14. Accordingly,the application device 1200 may also include one or more heatingelements 1260 in communication with the chamber 1222. The heatingelement(s) 1260 may be any type of device capable of melting the solidadhesive within the chamber. As used herein, the term “melting” meansraising the temperature of a solid adhesive to its melting point or atemperature at which it will flow. As with some of the adhesivesdescribed above, the heating element(s) may be capable of heating theadhesive within the chamber 1222 up to at least 60° C. and in some casesbetween 60° C. and 69° C. In some examples, the heating element(s) 1260may be ceramic or resistive heaters. One or more heater housings 1262may be coupled to the body 1220 via clamp 1264 for holding the one ormore heating elements 1260, as shown in FIG. 13e . Accordingly, the body1220 may be made of a heat-conducting material,

As shown in FIGS. 14 and 16A-16B, a solid adhesive 120 is melted in thechamber 1222 by one or more heating elements 1260 and dispensed onto afixation device 110. The nozzle 1230 may be shaped to dispense a meltedadhesive 120 as a bead 122 (FIG. 14) or a ribbon 124 (FIGS. 16A, 16B).Beads 122 of adhesive may be dispensed into the dimples 934 of a dimpledplate, such as plate 930, as shown in FIG. 15. Accordingly, the nozzle1230 may be shaped to dispense a volume of adhesive 120 that will fitwithin the dimple and, in some eases, create a meniscus above the platesurface 932. To create a ribbon 124 of adhesive, the nozzle 1230 mayhave a more narrow opening, as shown in FIG. 16A, which may depart amore thin and flat shape to the dispensed adhesive. In some examples,the application device 1200 may be provided with a fixed nozzle shape,such that different application devices are used to create either a bead122 or ribbon 124 of adhesive. In other examples, a single applicationdevice 1200 may have a set of interchangeable nozzles for creatingeither a bead or ribbon, or various sizes and shapes of beads orribbons, are provided and may be changed out depending on the particularapplication. Alternatively, the application device 1200 may be providedwith a dual-shaped nozzle that can be toggled or flipped between abead-dispensing nozzle and a bio dispensing nozzle.

In other examples, heating and melting of the adhesive can beaccomplished without an application device. Heating of the adhesive canbe done preoperatively to form an assembly, can be done outside the bodybut in the operating room to customize implants at the time of surgery,or can be done during surgery, in the body, when the bond is neededwithin the human body. Any suitable heat generating apparatus can beused to heat and soften or spot weld the adhesive material, such as alaser, a hot air gun, a small welding or soldering gun, or a Bovie tip.

V. Illustrative Methods

At least two fixation methods are contemplated herein. In a firstexample method, illustrated in FIG. 17, adhesive 120 is applied directlyto a site of interest, such as a bone fracture or osteotomy, without theuse of another fixation means such as a plate, pin or screw.Accordingly, the adhesive 120 alone is used to affix a first bonesegment 1710 to a second bone segment 1720. FIG. 18 is a flowchart of anexample method 1800 for affixing at least two bone segments. In a firststep, a bead of adhesive 122 is applied in a melted state to a firstbone segment and a second bone segment in abutment with the first bonesegment (1810). The adhesive is then cured, thereby affixing the firstbone segment to the second bone segment (1820). As used herein, theterms “cure” or “cured” should be interpreted in its broadest possiblesense to include any means, process or state by which the adhesive isallowed to set or transition from a melted to a solid or semi-solidstate, thereby joining the surfaces it contacts, in some cases, theadhesive may be cured over time, without any external assistance. Inother examples, heat, pressure or light may be applied to aid in curingof the adhesive. To join the at least two bone segments, at least onebead of adhesive may be applied to the first and second segments.Additional stability may be provided by dispensing a bead of adhesive onmore than one seam between abutting bone fragments.

This method of joining bone may be useful in a number of situationswhere plating systems are not feasible. There are a number of advantagesin using such a plate-less bonding technique including: the eliminationof the need for plates and instrumentation as well as simplification oftechnique for operating room personnel: the elimination of the need forsubsequent plate removal that is often necessary due to the plate'sinterference with extensor tendon function in the hand or itspalpability beneath the scalp; and the reduction of operating room time.For example, the method can be used in place of a plate, pin or screw,such as certain types of hand and craniofacial fractures where boneplates may be contraindicated such as: hand fractures close to thearticular surface where there may be inadequate room for placement of aplate; hand fractures close to the ephiphyseal growth plate in childrenwhere there is inadequate room for plate placement; non-displaced orminimally displaced hand and craniofacial fractures requiringstabilization, the fractures being in locations, where placement ofplates is not feasible; severely comminuted fractures wherestabilization by pure bonding (without plates) is the only option; andhand fractures in the elderly patient in whom plate placement may not befeasible due to confounding medical issues such as inadequate bone stockamenable to other modalities.

Another example method is illustrated in FIGS. 19 and 20. In thisexample method, a plate 1930, which may include any of plates 130-1030,is used to affix a first bone segment 1910 and a second bone segment1920. A flowchart of an example method 2000 for affixing at least twobone segments with a plate is shown in FIG. 20. In a first step, anadhesive is applied in a melted state to a plate configured to beaffixed to a bone (2010). The adhesive may either be directly applied tothe plate itself, or may be applied to the surface of a bone where theplate is to be affixed. The plate is brought into contact with a firstbone segment and a second bone segment in abutment with the first bonesegment (2020) and the adhesive is cured, thereby affixing the plate tothe first bone segment and to the second bone segment (2030). In someembodiments, the adhesive is melted and dispensed onto to the plate byan application device, such as devices 140 or 1200 described above.

In some examples, the plate 1930 may include a dimpled portion 1934,having one or more dimples, and a bioactive portion 1932, which mayinclude at least one medicinal agent. The bioactive portion 1932 may bebrought into contact with the first bone segment 1910 and the secondbone segment 1920 in the area where the second bone segment abuts thefirst bone segment 1910, such as at a seam 1940. The dimpled portions1934 are placed on the first 1910 and second bone segments 1920, oneither side of the seam 1940.

VI. Conclusion

While various aspects and embodiments have been disclosed herein, otheraspects and embodiments will be apparent to those skilled in the art.The various aspects and embodiments disclosed herein are for purposes ofillustration and are not intended to be limiting, with the true scopebeing indicated by the following claims.

I claim:
 1. A method for reattaching a removed section of bone to insitu bone without use of a mechanical fixation implement, the methodcomprising: positioning the removed section of bone in an abuttingrelationship with the in situ bone; applying a bioabsorbable polymeradhesive in a melted state to a removed bone and the in situ bone;maintaining the position of the removed bone relative to the position ofthe in situ bone; and allowing the adhesive to set and affix the removedbone to the in situ bone.
 2. The method of claim 1, wherein thebioabsorbable polymer adhesive is applied to the removed bone sectionprior to positioning the removed bone section into the abuttingrelationship with the in situ bone, whereby the adhesive is applied tothe in situ bone.
 3. The method of claim 1, wherein the bioabsorbablepolymer adhesive is applied to the in situ bone prior to positioning theremoved bone section into the abutting relationship with the in situbone, whereby the adhesive is applied to the removed bone section. 4.The method of claim I, wherein the bioabsorbable polymer adhesive is aheat-meltable polymer.
 5. The method of claim 4, wherein theheat-meltable polymer is a polymer blend.
 6. A system comprising: abiocompatible plate configured to be affixed to a bone surface; and anadhesive comprising a heat-meltable biocompatible polymer and adapted toaffix the plate to the bone surface without the use of a mechanicalfixation implement.
 7. The system of claim 6 wherein the plate isresorbable.
 8. The system of claim 6 wherein the plate is porous.
 9. Thesystem of claim 6 wherein the plate includes a bioactive portionincluding a medicinal agent.
 10. A system for affixing a plate orremoved section of bone to an in situ bone, the system comprising: anadhesive comprising a heat-meltable biocompatible polymer and adapted toaffix the plate or removed section of bone to the in situ bone withoutthe use of a mechanical fixation implement; an applicator devicecomprising a chamber for containing the adhesive, a heating element incommunication with the chamber, a nozzle for dispensing the adhesive, apiston slidably disposed within the chamber for advancing the adhesivetowards the nozzle, and a control mechanism for controlling release ofadhesive from the nozzle.
 11. The system of claim
 10. Wherein thecontrol mechanism comprises an actuator in operative communication withthe piston having an active position and a released position, wherebymoving the actuator from the released position to the active positioncauses the piston to advance within the chamber towards the nozzle; anda spring biasing the actuator in the released position, whereinreleasing the actuator from the active position retracts the pistonwithin the chamber away from the nozzle and creates a negative pressurewithin the chamber.